neptunium
Sign in to saveNeptunium is a chemical element; it has symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. It is named after Neptune, the planet beyond Uranus in the Solar System, which uranium is named after. A neptunium atom has 93 protons and 93 electrons, of which seven are valence electrons. Neptunium metal is silvery and tarnishes when exposed to air. The element occurs in three allotropic forms and it normally exhibits five oxidation states, ranging from +3 to +7. Like all actinides, it is radioactive, poisonous, pyrophoric, and capable of accumula
AI overview
Neptunium is a radioactive metal with 93 protons that was the first element heavier than uranium ever discovered, named after the planet Neptune to follow uranium's naming after its planet. Because neptunium is radioactive, toxic, and capable of accumulating in the body, it poses significant health and environmental concerns despite having limited practical applications.
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Article
35 sectionsContents
- Characteristics
- Physical
- Alloys
- Chemical
- Atomic
- Isotopes
- Occurrence
- History
- Background and early claims
- Discovery
- Subsequent developments
- Production
- Synthesis
- Purification methods
- Chemistry and compounds
- Solution chemistry
- Hydroxides
- Oxides
- Halides
- Chalcogenides, pnictides, and carbides
- Other inorganic
- Organometallic
- Coordination complexes
- Solid state
- In aqueous solution
- Applications
- Precursor in plutonium-238 production
- Nuclear weapons
- Physics
- Role in nuclear waste
- Biological role and precautions
- References
- Bibliography
- Literature
- External links
Neptunium is a chemical element; it has symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. It is named after Neptune, the planet beyond Uranus in the Solar System, which uranium is named after. A neptunium atom has 93 protons and 93 electrons, of which seven are valence electrons. Neptunium metal is silvery and tarnishes when exposed to air. The element occurs in three allotropic forms and it normally exhibits five oxidation states, ranging from +3 to +7. Like all actinides, it is radioactive, poisonous, pyrophoric, and capable of accumulating in bones, which makes the handling of neptunium dangerous.
Although many false claims of its discovery were made over the years, the element was first synthesized by Edwin McMillan and Philip H. Abelson at the Berkeley Radiation Laboratory in 1940. Since then, most neptunium has been and still is produced by neutron irradiation of uranium in nuclear reactors. The vast majority is generated as a by-product in conventional nuclear power reactors. While neptunium itself has no commercial uses at present, it is used as a precursor for the formation of plutonium-238, which is in turn used in radioisotope thermal generators to provide electricity for spacecraft. Neptunium has also been used in detectors of high-energy neutrons.